It depends, I know 150 and 200 amp service use the exact same wire, but many go to 150 because you can still pull the permit as a homeowner, 200 requires someone with a ticket. Not sure on 100 though.

 

Standard USEB residential service cables come in 60A, 100A and 200A sizes. If its conduit and copper it could be anything.

 

That doesn't add up although I don't know what the actual loads are. Have you put a meter on it to see what the actual load is? The main breaker could be weak and tripping at a lower limit.

 

The house has a 100 amp panel. The shop is fed off that panel. It trips when when we are in the shop and my Mom is in the house. It only happens once in a while. I put my meter on it and it will show max load and it will spike over 100 amps on one leg. We will be adding the new service this spring. Im sure it spikes when the washer, dryer, oven, furnace, tv, refrigerator, and we are in the shop with all the lights on heater, fans,fridg, air compressor welder etc...

 

I assume you are changing the utility feeder when you say 'service'. Up here you can't just change the panel to 200A, beside it being dangerous it would be contrary to our canadian electrical code.

 

Yeah, it will be a new service mast. The house, the garage and the shop are all connected together. The garage is in the middle. We plan on putting a new 200 amp panel there. Then sub feeding to the shop and the house. This will give us a panel to wire the new garage. We built a (30x67) garage that connects the shop (40x70) to the house. We might even put a 400 amp service in and run 100 amps to the house and 200 amps to the shop. As far as the codes go we can derate the wire and run a 2/0 THHN in the new service mast. We will probably run 3/0 only because I have some spare pieces.

 

I'm not 100% sure but I think you can get type USE direct bury wire in any size. In copper or aluminum.

 

Yes but standard stock is in the ones I mentioned. You guys might get better selection where you are. If you want an odd size here you have to buy a whole roll.

You also have a lot more space than our OP. He's just house and garage and likely one, maybe two operators of the equipment.